In an effort to improve disk performance, disk manufacturers have created disks with caches. Although previously these caches were used when reading data from the disk, they have recently also been used when writing data to the disk. In particular, when an operating system requests that data be written to a disk, the disk controller may report that the data has been written before the data is actually transferred from the disk cache to non-volatile disk memory. Also, the order in which the data is written to the non-volatile disk memory may be different from the order in which the data is received by the disk controller. These behaviors are problems for systems that attempt to maintain consistency.
The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where some embodiments described herein may be practiced.